The rapid increase in demand of reactive dyestuff is due to their excellent wet fastness and simple dyeing operation. Reactive dyestuff can be applied by various traditional processes but these consume a considerable amount of energy, water and chemicals. Due to increasing demand for woven and knitted fabrics, energy consumed in reactive dyeing processes is increased. It has become necessary to look for energy efficient techniques which use less energy, water, chemicals etc. Use of more water in washing requirements leads to more effluent and effluent disposal becomes more concern. This paper is mainly focussing on basic principle and recommended dyes for E-control process. In this process, the reactivity of the dyestuff is exploited together with the drying behaviour of the fabric in such a way that optimum colour yields can be achieved without the use of large and aggressive volumes of alkali. Hence, it is eco-friendly and economical. This E-control process is also an energy efficient technique as it is a combination of continuous batch process and drying process.
The continuous dyeing of cotton using reactive dye is gaining importance over the traditional batchwise techniques owing to the major advantages in terms of uniformity of shades in long yardages, high productivity, low utility cost in terms of consumption of dyes, chemicals, water, energy and low effluent generation. Continuous dyeing provides fabrics with a uniform visual appearance, freedom from creasing. Recently, here are changes in the dyeing process of cellulose using reactive dyestuff by continuous application. There are so many factors for such changes.
Some of these factors are:
- The need of superior quality
- Ecofriendly application method
- Cost reduction by minimising the use of energy and water
- Quick response through "right first time".
Considering such a factor, effective coordination between a dyestuff manufacturer, textile processor, machinery producer has lead to ongoing improvements in the continuous dyeing process of cellulose using reactive dyestuff. Various dyeing methods are adopted depending upon the type of substrate, selection of dye, availability of machinery and processors choice.
This article gives detailed information about the E-control dyeing process i.e. we are concentrating on its basic principle and possible shades, its dye and fibre requirements. As it is more economical, energy saving and ecofriendly, it has been commercialised.
The authors are associated with the Textile Department, ICT
Originally Published in Journal of Textile Association, May-June, 2011.